Tube base and socket



Oct. 9, 1934. J, RM N 1,976,561

TUBE BASE AND SOCKET Filed Aug. 16, 1933 2 Sheets-Sheet l INVENTOR JULI05 H/RMA/V/V ATTORNEY Oct. 9, 1934. J, HIRMANN TUBE BASE AND SOCKETFiled Aug. 16, 1933 2 Sheets-Sheet 2 u m MATHHIHH Patented Oct. 9, 19341,976,561 TUBE BASE AND SOCKET Julius Hirmann, Hillside, N. J., assignorto Radio Corporation of America, a corporation of Delaware ApplicationAugust 16,1933, Serial No. 685,347

5 Claims.

My invention relates to vacuum tubes and the like, and more particularlyto bases and sockets of the base thus adding to the overall length ofthe tube. These tubular contact pins are connected to the electrodeelements of the tube by leading-in wires threaded into and soldered tothe pins. The conventional socket has spring contacts which engage thecontact pins of the base. The socket contacts extend radially out- -wardand are fastened-at their ends or intermefiate their ends to the bottomof the socket by rivets or the like. 7 The socket is inherently largeand bulky and extends considerably beyond the outline of the base of thetube. An increase in the number of contact pins on the base decreasesthe spacing between the pins, increases the tendency for voltagebreakdown through the base and greatly increases the difliculty ofbasing the tube particularly the threading of the leading-in wires intothe contact pins.

socket has likewise reached a practical limit because of lack of spaceand because ofltheincrease in the tendency of :voltage breakdown throughthe socket. Assembly of the socket due to the number of parts requiredis likewise made more difficult.

Not only has the practical limit been reached in the number of contactswhich can be mounted in a conventional way in tubebases and sockets ofconventional size, but tube bases and sockets only about one-half theconventional size must .be made with as many or even more contacts thanthe bases and socket of conventional size. The

- usual number of conventional contact pins cannot be mounted in theconventional way on the smaller base, yet a corresponding reduction insize of the contact pins will result in pins which are too weak forpractical use, which do not have enough contact area and which offergreat difficulty in the threading of the leading-in wires into the pins.Furthermore, there is a practical limit in the reduction of the diameterof the contact pins and of the leading-in wires, as the wires must besufficiently large to carry the necessary current and also stiff enoughto thread easily into the pins, which must, of course, have a boresomewhat larger than thewire. n V v A reduction in the size of theconventional socket and its contacts will result in contacts which areThe number of contacts which can be accommodated by the conventional tooweak for practical use, which do not have sufficient contact area andwhich increase the difficulty of assembling the socket. It would not bepractical to materially reduce the size of con-' tacts in the socket andstill have these contacts. properly cooperate with base pins which werenot materially less than the conventional size.

The conventional contact pin is in efiect riveted into the base byupsetting or spinning the inner end of the pin over theinside of thebottom of the base. The inner end is thus enlarged and in effectincreases the diameter of the pin 'so that more rcomis-required forspacing between the pins. As it is not feasible to reduce the diameterof the pins, the space required for fastening the pins to thebase cannotbe reduced, nor can smaller socket contacts be used as the conventionalsocket contact is larger than the base pin.

One object of my invention is to provide a base and socket which can bemade smaller than the conventional base and socket and yet have as manyor even more contacts of ample area and properly spaced so that theelectrical and mechanical properties of the smaller base and socket willmeet all requirements.

Another object of my invention is to provide a base so constructed thatthe attachment of the leading-in wires to the contacts is simpler andeasier than soldering to tubular contact pins.

A further object of my invention is to provide a base and socket havingmechanically strong contacts which are so arranged that more angularspace is made available for the contacts than in the conventional baseand socket'and which are madev to occupy less angular space on the baseand socket than the contact pins and socket contacts commonly used, yethave as great or even greater contact area than the conventional pin andsocket contacts.

Still another object of my invention is to provide "improved base andsocket contacts which are simple and inexpensive to make.

The novel features which I believe to be characteristic of my inventionare set forth with particularity in the appended claims, but theinvention itself together with further objects "and advantages thereof,will best be understood by reference to the following description takenin connection with the accompanying drawings in which 10 Figure 1 showsa vacuum tube having a base constructed in accordance with my invention.

Figure 2' is an enlarged'top view of the base shown in Figure 1 with thebulb removed.

Figure 3 is a longitudinal section of the lower 110 llU ' tion with thetube shown in Figure I inserted in the socket.

Figure 8 is a top View of the socket shown in Figure 7 with parts insection-to show detailsof construction.

Figure 9 is a longitudinal cross-section of the empty socket of Figure 7taken along the line 9-9 of Figure 8. Figure 10 is a perspective view ofthe top member of the socket of Figure 9.

Figure 11 is a longitudinal cross-section of the socket shown in Figure7 with a tube base partly inserted, and

Figure 12 is a perspective view of-a contact and locking block made inaccordance with my invention.

The vacuum tube annular shown in Figure l of the drawings has anevacuated bulb 15 which encloses the usual cathode and other electrodes,and has cemented to it a cup-shaped base 16, pref erably oimoldedinsulation. The base shown in Figures 1 to 4 has radial bosses 17 spacedaround 35' lengthwise of the base.

its periphery near the bottom and extending These bosses have inclinedshoulders 18 at the top and tongues 19 at the bottom to position andsupport the base contacts. As best shown in'Figure 4'the base has radialgrooves 20 which register with'the underside of the bosses l7 andterminate in longitudinal slots 21= opening into the aperture 22 in thebottom of the base,

U-shaped contacts 23 consisting of fiat strips or ribbons, as shown'inFigures 5 and 6, are wrapped around and carried by the bosses 17; Theends oi the contacts are brought together and welded to fasten thecontacts in place on the bosses and to form connecting lugs 24 whichfacilitate and simplify the; connecting of the lead wires 25 to the basecontacts 23. When the tube is based these connecting lugs practicallyadjoin the lead wires 25 which project through the aperture 22 inthe-base shell. The lead wires 25 may be inserted in the connecting lugsand then welded to a the lugs, thus making a good electrical connectionmoreeasily than by soldering and eliminating threading of the lead wiresinto the contact pins. Since the width of a boss with a contact mountedon it may be less than the diameter of the conventional tubular contact,and since the contacts are spaced around the exterior of the baseinstead of in a circle'on the bottom of the base near the rim as is-donewith tubular contacts, more such contacts can be accommodated on a baseof the usual size,,or the size of the base can be materially reduced andstill the maximumnumber or" contacts now feasible for the usual sizebase can be'used. These flat contacts are strong and provide amplecontact area.

The contact members 23 may to advantage be made'of nickel which can veryeasily be'worked and welded. They may be made in various ways, but Iprefer to cut them from metal ribbon and formthem as shown in Figure 6,as'it is easier to shape the metal ribbon into such aflat contact thanit is to make the usual type of tubular contact. By mounting thecontacts on bosses projecting radially from the side of the base theoverall length of the based tube is made materially less than that of asimilar tube having tubular contacts in the bottom of the base.

It is obvious that the base canbe registered withv the socket in variousways; for example, by a stud or projection onthe base shell to enter acorresponding slot in the socket, by one boss of different size than theother bosses, or preferably by spa cing two of the bosses further apartthan the others, as indicated at a in Figure 2.

A socket constructed in accordance with my invention and adapted for usewith the tube base above described is shown in Figures 7 to 11inclusive. It has ametalli-c cup-shapedmember 26 with a central stub 27in the bottom and a flange like lip 28:. The metal cup 26 is anelectrical shield for the'tube base and thus assists in preventinginterstage coupling which is highly desirable in modern apparatus usinghighly "sensitive tubes.

Supported on the flange like lip 23 is an annular'or ring-shaped member29' riveted to the lip. The annular member 29 overhangs the interior ofthecup-shaped member 26 and, has radial undercut'slots or. grooves'30,best shown .in Figure 10. These slots 30, which are enlarged at 31adja-' cent the opening in the annular member 29, also have transversedepressions or grooves 32 by means of which the socket contacts. 33 arepositioned in the slots.

Each socket contactispositioned in one of theundercut slots 30, andhason-its outer end a lug 34and on its inner end a downwardly extendingtongue 35 positioned in the enlarged end 31 of the slot The socket.contact is: formed with a hump .36 to fit into a .groove 32. Aninsulating block 37, with a projection 33forregistering with the groove32, is clamped between the socket contact 33 and theflange-likelip 28 tolock the socket contact in place No rivets, or bolts or the like areneeded to fasten the contacts to the socket. The contact spring need notbe punched for a rivet or. bolt, hence the spring contact is strongerand it. may be made more compact than has heretofore been feasible. 7

As bestshown in Figure 8 longitudinal slots 39 on-the insideof theannular member 29' permit a tube base such as shown in Figure 1 'to bein serted in the socket. A. protector disc 40 normally held against thebottom of the annular member 29 by a biasing spring 41 centered on thestub 27. prevents the entrance of foreign objects into the empty socket,.and also prevents accidental touching of the socket contacts. Thesocket'may .be attached to a sub panel 42 by-means of nuts and bolts 43,as shown in Figure 7.-

Whenthe base is inserted. in the, socket; the bosses are registered withthe slots 39, and the tube is pushed down into the socket against thedisc 40 until the tops of the bosses clear two down-,

wardly projecting lugsv b and 0 provided on the annular member to insurethat the bosses will not accidentally engage and twist the tongues 35 ofthe contacts while the base is being rotated into place. Anotherdownwardly extending lug .d, which is longer than lugs bF'and c,prevents rotation of the base in a counter clockwise direo-' 1 tion,-asviewed in Figure v8, but permits rotation of the base in a clockwisedirection to'bring the contacts "33 on the socketand the contacts 23 onthe base into alignmentJ When this position has been reached, pressureis released'from the' tube and thebias'ings'pring-41 forcesthe' base16'up against the tongues 35 of the contacts 33 as clearly shown inFigure 7 to provide electrical contact between the base and socket, thetongue 35 giving an inward wiping action as the biasing spring pushesthe base into place. This locks the tube base in the socket and preventspoor operation of the tube due to loose contacts brought about by shockand jar, thus making this construction highly satisfactory for mobileand portable use.

It will thus be seen that I have provided a base and socket in which themaximum number of contacts which is now feasible to use on theconventional base and socket can be materially increased and still havethe base and socket fully meet the electrical and mechanicalrequirements of such tube bases and sockets. In accordance with myinvention I can materially reduce the size of the usual base and socketand still properly accommodate as many contacts as can now be used onthe base and socket of usual size. The threading of lead wires in thetubular contact pins has been eliminated thus expediting manufacture andthe electrical connection between the contact and leading-in wires hasbeen materially improved. In addition to providing an improved method ofattaching the contacts to the socket, the socket electrically shieldsthe tube base and securely retains the tube base in place against theusual vibration and shock encountered in portable and mobile use. Theshielding and wide spacing of the contacts which reduces interleadcapacity also makes a base and socket embodying my invention mostsuitable for short wave use.

While I have indicated the preferred embodiments of my invention ofwhich I am now aware and have also indicated only one specificapplication for which my invention may be employed, it will be apparentthat my invention is by no means limited to the exact forms illustratedor the use indicated, but that many variations may be made in theparticular structure used and the purpose for which it is employedwithout departing from the scope of my invention as set forth in theappended claims.

What is claimed as new is,

l. A vacuum tube base including an annular member having spaced radialbosses on the exterior thereof, said bosses having surfacessubstantially perpendicular to the periphery of said annular member, andribbon contacts wrapped around said bosses to lie flat against saidperpendicular surfaces for providing contacts on the outside of saidbase.

2. A vacuum tube base including an annular member having spaced radialbosses on the exterior surface near one end, said bosses having surfacessubstantially perpendicular to the periphery of said annular member, andribbon contacts wrapped around said bosses to lie fiat against theperpendicular surfaces of said bosses for providing contacts on theexterior of said base, and lugs on said contacts adjacent the bottom ofsaid base for leading-in wires.

3. A Vacuum tube base including a cup-shaped member having spacedlongitudinal bosses on the periphery and near the bottom and havingradial grooves on the outside bottom registering with said bosses forpositioning leading-in wires extending through the bottom of thecup-shaped member, said bosses having surfaces substantiallyperpendicular to the periphery of said cupshaped member, and ribboncontacts wrapped around said bosses to lie fiat against saidperpendicular surfaces and lugs on said contacts at the bottom of saidbase for the leading-in wires.

4. A vacuum tube base including a cup-shaped member having an aperturein the bottom thereof, spaced lon itudinal bosses on the periphery andnear the bottom of said cup, said bosses hav-. ing surfacessubstantially perpendicular to the periphery of said cup-shaped member,ribbon contacts wrapped around said bosses to lie fiat against saidperpendicular faces, the bottom of said cup-shaped member having radialslots registering with said bosses and extending from said aperture tothe rim of said cup, and lugs on said contacts registering with saidslots for receiving leading-in wires extending through said aperture andpositioned within the slots in said base.

5. A vacuum tube base including an annular member having a plurality ofspaced longitudinal bosses on its periphery, said bosses having surfacessubstantially perpendicular to the periphery

